At their most ferocious, the migrating grasshoppers can form swarms up to 9.6 square miles (25 square kilometers) that can travel more than 300 miles (500 kilometers) a day searching for food, according to the Australian Plague Locust Commission. A swarm of just 0.4 square mile (1 square kilometer) can contain up to 50 million locusts and consume 11 tons (10 metric tons) of vegetation every 24 hours.

The New South Wales minister for agriculture, Ian Macdonald, said work has been "feverish" ahead of the anticipated outbreak.

Tens of millions of dollars in damage could be done to crops, pastures, orchards, gardens, and sports fields.

"Fortunately the number of new hatchings continues to drop," Macdonald said. "On the other hand, forecasted warmer weather will speed up locust maturity, and control authorities expect to see more adult swarms developing."

But despite chemical stockpiles and mobile response teams being dispatched across the state, Macdonald said it will be impossible to prevent all damage.

"Locusts are highly destructive creatures, no matter the size of their population," Macdonald said.

"Every effort is being made to reduce damage to a minimum, limit future swarms, and curb migration and future egg-laying. But with 11,008 hatching reports in NSW so far and more swarms in the coming weeks, some damage to crops and pastures must be expected."

Damage Done

Last month government agencies in Sydney and other regions were expecting the hatchings to be so numerous that officials began assembling mobile response teams to deliver chemicals to properties as soon as the locusts started hatching.